As consumer demand grows for ever-richer services and connected lifestyles, mobile networks will evolve. The mobile industry is already hard at work defining the technical solutions that will allow mobile networks to meet the growing demand for wireless broadband services. Mobile networks continue to develop at an exciting pace. Future mobile networks may well support services beyond that of today's multi-megabit fixed connections, while the amount of data traffic on mobile networks could surpass that of today's broadband connections in the next decade. A radio access technology which is being developed and which would realize such networks have been given the name Long Term Evolution of Universal Terrestrial Radio Access Network—or LTE for short.
LTE will be used for mobile, fixed and portable wireless broadband access, and will offer a number of benefits to operators, aimed at increasing capacity, reducing network complexity and thus lowering deployment and operational costs. It will enable operators to meet the growing demand for mobile data solutions, making it possible for richer services to be delivered to consumers more cost effectively.
LTE defines new radio connections for mobile networks, and will utilize Orthogonal Frequency Division Multiplexing (OFDM), a widely used modulation technique that is the basis for Wi-Fi, WiMAX, and the DVB and DAB digital broadcasting technologies. The targets for LTE indicate bandwidth increases as high as 100 Mbps on the downlink, and up to 50 Mbps on the uplink. However, this potential increase in bandwidth is just a small part of the overall improvement LTE aims to provide. LTE is optimized for data traffic, and it will not feature a separate, circuit-switched voice network, as in 2G GSM and 3G UMTS networks.
LTE is being developed in the 3rd Generation Partnership Project (3GPP) and focus on the evolution of the 3G RAN (Radio Access Network). In 3GPP there is also a work item called SAE (System Architecture Evolution) that focus on the evolution of the Core Network. Both LTE and SAE focus on developing a packet-only system. LTE and SAE are being specified without co-existence for CS services fully taken into account.
A possible need for interaction with the CS domain in certain cases has however been discussed. For instance when handling mobility for a VoIP (Voice over Internet Protocol) connection to a terminal that moves into an area where VoIP cannot be provided. More information about some different solutions that are being discussed can be found in chapter 7.19.1 of the 3GPP technical report TR 23.882 v1.5.0 “3GPP System Architecture Evolution: Report on Technical Options and Conclusions”, published in November 2006.